At one point, a voicebox with a recording of Darth Vader's voice is found. Ewan McGregor, the voice of Rodney Copperbottom, played a young Obi-wan Kenobi in the Star Wars prequels, the third of which being released in 2005, the same year as this film.
Originally, Rodney's co-passenger in the cross-town express sequence was an old lady knitting calmly. For some long shots, the old lady is simply colored red rather than replaced with Fender. This version of the scene was the one used in movie clips featured in the film's video game.
When Rodney and Fender take the Crosstown Express, the shots of the outside of the ball show it spinning in the air. But in the shot from inside the ball, it's just flying along straight and not spinning.
Just before Rodney takes the city ball express, you can see him standing on a giant cog turning downwards. In the wide shot, the cog above him clearly has a robot on it too, yet when Rodney hops off, the cog above him comes down, and there is no robot to be seen